Richard Fortey

TRILOBITE!

Eyewitness to Evolution

I suppose the exclamation mark placed after the title of this book is intended to make it sound more exciting, but really it didn't need this gimmick, for it's one of the best popular science books to have appeared for a considerable time. Fortey is a fine writer and the enthusiasm he feels for his subject leaps at you off the page.

If, like me, you thought of trilobites as rather uninteresting creatures vaguely resembling woodlice, you're in for a shock. They varied enormously in size: some were no bigger than a lentil, others as big as a lobster or a serving dish. Some walked on the ocean floor, some swam freely; some lived on decaying matter in the almost anoxic environment of the sea floor, others were actively predatory. They were found in almost every part of the ancient world, although curiously they never colonised fresh water. But it's their appearance which was truly astonishing. They grew all manner of spines: some had straight spines, some had curly spines like a ram's horns, and some even had spines with smaller spines sprouting from them. Some could roll into a ball, and then they might take on an appearance reminiscent of those little Japanese carvings called netsuke. One, which has only recently been discovered and is still unnamed, sprouted a large trident from its head: a singularly appropriate ornament for an exclusively marine creature.

Then there were their eyes, to which Fortey devotes a complete chapter. The lenses were made of transparent calcite, and most had multiple lenses rather like those of modern insects with compound eyes. The calcite was arranged in elongated prisms, forming lenses whose optic axes were oriented exactly at right-angles to the surface of the eye. The whole eye, which might be a long semicircular structure extending most of the way round the animal's head, might have hundreds or even thousands of such lenses, their axes pointing in different directions to give almost 360 degree vision. There was also another kind of eye, with larger spherical lenses arranged in rows of extreme regularity.

Trilobites are interesting, not just in their own right, but because of what they can tell us about evolution and geology. There were trilobites on earth for almost 300 million years. They first appear quite rapidly in the Lower Cambrian, about 540 million years ago, and reach their peak of diversity and success in the Ordovician, at the end of which there was a mass extinction, probably caused by a great glaciation centred in North Africa. But some trilobites survived. They did not finally disappear until the Permian, 260 million years ago. By tracing their evolution we can shed light on the 'Cambrian explosion', an event which Fortey has reservations about. And the trilobites can help us to understand the vast geological shifts and processes that gave rise to our modern continents, for during their long existence the world was remade twice.

Fortey brings all these topics to life, but his gaze is not fixed exclusively on the remote past. He intersperses his account with anecdotes from his own fossil-hunting, including one occasion when he almost died after being stung by a giant hornet in China; a colleague at the Natural History Museum later complained that he had failed to bring the insect back with him for identification. He is always conscious of the human beings who have been responsible for discovering the secrets of the trilobites, and here there are some dramatic tales to be told. Rudolf Kauffman, a German palaeontologist of Jewish descent, had a love affair with a Swedish girl before the war which ended tragically; he tried to join her in Sweden in 1941 but was murdered by Nazi guards who happened to recognize him.

Another strange story concerns Jacques Deprat, a French geologist early in the twentieth century who did important research and exploration in Vietnam. At first he achieved renown for his work but then he was accused of falsifying his data and was disgraced. But, in an odd sequel to this, Deprat wrote an account of the affair in a novel, and went on to become a successful novelist under the name of Herbert Wild. He died in a mountaineering accident in 1935, and the circumstances of his death were curiously similar to those he earlier described in a novel.

Fortey is interested in the connections between fiction and trilobites; his book begins with a quotation from Thomas Hardy's story 'A Pair of Blue Eyes', in which the protagonist falls down a cliff and finds himself facing death reflected in the eyes of a fossil trilobite. A literary theme runs through the book. In his final chapter, Fortey considers the hostility that many people still feel for science. There is a belief, going back as least as far as William Blake, that science is somehow cold and dispassionate, and therefore opposed to art, which is creative. One of Fortey's motives in writing this wonderful book seems to have been to show this idea up for the nonsense it is. He has succeeded triumphantly. The book is enlivened throughout with touches of humour, and at times it rises to passages of lyrical writing that never seem forced. I can't resist closing with a quotation to give the feel of it.

"Now, by a twist of fortune, I am privileged to create my own possible worlds: vanished worlds, written in a geography generated in my imagination, and argued out with a dozen of my colleagues. I have dreamed of chains of volcanic islands belching fumes and spewing lava into archipelagos swarming with trilobites and nautiloids. I have seen these animals suffocate on a ravaged sea floor, killed and immortalized at one stroke. On a Welsh mountainside I have tested the truth of such an ancient tragedy by breaking a hard rock in which memories of volcanic ash render the surface as grey as woodsmoke, and in which lies entombed the shadow of a trilobite, petrified to tell of its dreadful end. In my mind's eye I have seen volcanic archipelagos collapse and die as continent collides with continent, squeezed between masses so vast that an ancient Stromboli might be as vulnerable as a grape in a nutcracker. This is the Ordovician world, a globe so alien that it bears little comparison with the atlas of today. There is land and sea, to be sure, but the continents are not those we have learned by rote in our first classroom. They are strange shapes, curiously arranged."

This is a brilliant book, to be read and savoured by anyone with a shred of curiosity about the world we live in and how it came to be.